This example is a little bit softer than the ones I mentioned. 'Latin' German is, I assume, letter-for-letter identical to blackletter German, just with noticeably different glyphs. Given, say, a box of correspondence, a German who'd never been trained to read blackletter could probably puzzle it out.
Akkadian and Sumerian were thousands of years old (and, obviously, long dead) when they got wiped out. And while Mycenaean Greek is not much different from classical Greek (with a gap of only a few centuries), it is written using a writing system entirely unrelated to that of classical Greek, which we assume was originally developed for some other unknown language because it fits Greek so poorly.
> “if we're to trade with the rest of Europe, those nations must understand German writing”
I don't see why this would make any difference. We trade with Japan (and had been doing so for centuries before Hitler). Recognizing the letters in a German contract isn't much good if you can't understand the words.
Akkadian and Sumerian were thousands of years old (and, obviously, long dead) when they got wiped out. And while Mycenaean Greek is not much different from classical Greek (with a gap of only a few centuries), it is written using a writing system entirely unrelated to that of classical Greek, which we assume was originally developed for some other unknown language because it fits Greek so poorly.
> “if we're to trade with the rest of Europe, those nations must understand German writing”
I don't see why this would make any difference. We trade with Japan (and had been doing so for centuries before Hitler). Recognizing the letters in a German contract isn't much good if you can't understand the words.